Thor Missile Guidance: What, Where and How

[YellowPinkie]

Missile Target Kits

The two targets per missile were set in the Guidance Laboratory at each complex HQ, where the individual missile's Target Data Sheets were compiled along with monthly corrections for weather etc. The required settings were then entered into the missile's guidance computer and the missile delivered to site and mated with the launch mount.

So from this statement, the targets were fixed at the RIM and the LRT/SRT arrangement serves only to correct for environmental conditions and to check that the missile is still going to go where intended?

How often were missiles shipped back to the RIM, either for a target change(?) or servicing?

More answers, more questions...

[P Bellamy]

Once mated to the launch mounts the missiles tended to stay there until removed for shipping back to the USA for training launches, repairs and modifications being done on the pad.
For example, of the three missiles originally mounted at Harrington in January 1960, "49" and "51" didn't leave again until the site was closed.
"Missile 50" was de-mated and removed following the accidental RP1 loading in August 1961, and a replacement missile arrived and was mated to LE 50 the following month.

The missiles (and the entire pad installations themselves) were subject to 15-day (17-Day from January 1962) and 30-Day (35-Day from July 1961) Periodic Inspections in situ.
Following Periodic Inspections, target changes ordered, replacement of the guidance system or other missile components etc., Sheet 4 was used to re-enter the required data into the missile's guidance computer while still mated to the launch mount.

[Dale]

Fascinating stuff all this and certainly a cure for insomnia hard copies all round I think.

Anyway Paul would it not be easier to scan the entire training course notes into a thread and then answer questions at your leisure

[P Bellamy]

Somehow I don't think Roy at Harrington museum would appreciate me doing that with his prized book...
I will continue to present the seriously condensed "highlights" for your reading pleasure.

[buccaneer66]

Been in the library again Paul I was in there last weekend?

[P Bellamy]

As previously promised, an example of how (and by whom) a basic procedure was carried out, in this case a Vertical Target Change.
This procedure would be carried out if a "change of target" order was received by the LCO after completion of Phase 1 of the launch countdown, i.e. after the missile had been raised and locked in Phase 2.

To refresh, each launch crew shift consisted of a core of six men, a TEW (Thor Electrical Worker) overseeing the power supplies, the Launch Control Officer and the Launch Control Console Operator in the LC Trailer, and an MMT (Missile Maintenence Technician) on each pad.

LCO	LCCO	MMT
Order “Carry out a vertical target change on the LRT”		Take station in EET
	Acquire LRT on present target
	AIRFRAME AZIMUTH selected
	ATTITUDE VERTICAL selected
	Control Point switch to LCT
		Report roll gimbal angle to LCCO
	Record reported roll gimbal angle.
	Target Change switch to TARGET CHANGE
	Target Selector switch to ALTERNATE TARGET
	Burst Selector switch to NOMINATED BURST
	Instruct MMT to place computer switches to LOCK
		Computer Switches to LOCK
	Control Point switch to EET
	Instruct MMT to carry out vertical target change on LRT
		Select ALTERNATIVE TARGET
		Reverse Progress Indicator to ALIGN 2
		Azimuth Reference switch to AUXILLARY
	Pass on new mirror angle as required
		Set new mirror angle
	Pass on new roll gimbal angle as required
		Set new roll gimbal angle
		Hand-set pitch and yaw null gauges into green
		Hand-set roll gimbal to give null meter gauge in green, having checked deflection both sides of null
		Azimuth Reference switch to THEODOLITE
		Check stab gyro null gauges all in green
		Advance Progress Indicator to ALIGN 3
		Check roll null meters tends to null roll gimbal angle correct
		Confirm EN Potentiometers driving to normal values
		Advise LCCO “Target changed, take LCT Control”
	Control point switch to LCT
		Observe Control Point Light is to LCT
	Select AUTOMATIC STOP (Non-operational countdowns only)
	Computer Switches to ADJUST
	Set Vg Potentiometers to new values, do not zero
	Wait until ADVANCE appears
	Advance Progress Indicator to COMPLETE
	Select AIRFRAME REFERENCE
	Report “Target change completed Pad xx” to LCO
Order MMT to return to countdown station or evacuate as required		Return to station or evacuate as ordered
	Await instructions before operating target change switch

[Dale]

"Roy at the museum", interesting that Paul, when I joined their little band I was told they didn't have a Thor specialist and nobody seemed that interested, odd, but I learned to expect nothing else, keep the info flowing

[P Bellamy]

Well, they've roped me into doing a new Thor display there next year so I guess they do have a sort of "Thor specialist" on hand now.

[buccaneer66]

They couldn't do better Paul.

Ron has offered me a base there doing the Desborough stuff. (They must be desperate).

[P Bellamy]

What with co-opting the pair of us, do they realise what they've taken on?

Ron I've known for many a year now, and he's straight as a die, as is Roy.
It was great to chat to Roy's mum once again the other day, I was reminding them all of some things that we got up to when we were refurbishing the Ops Block ready for opening all those years ago that they'd long forgotten. I know some things went awry a number of years ago at the museum, but the team there now are back working in the right direction once again.

Having Desborough stuff in the Harringon Museum would be more than appropriate, what with it being originally built as Desborough's satellite airfield.

PB